From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
To: Bruce Richardson <bruce.richardson@intel.com>,
Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>,
Narcisa Ana Maria Vasile <navasile@linux.microsoft.com>,
Dmitry Malloy <dmitrym@microsoft.com>,
Pallavi Kadam <pallavi.kadam@intel.com>
Cc: dev@dpdk.org, honnappa.nagarahalli@arm.com, ruifeng.wang@arm.com,
feifei.wang@arm.com, nd@arm.com
Subject: [dpdk-dev] [RFC 2/5] eal: ensure memory operations are visible to worker
Date: Wed, 24 Feb 2021 15:20:15 -0600 [thread overview]
Message-ID: <20210224212018.17576-3-honnappa.nagarahalli@arm.com> (raw)
In-Reply-To: <20210224212018.17576-1-honnappa.nagarahalli@arm.com>
Ensure that the memory operations before the call to
rte_eal_remote_launch are visible to the worker thread.
Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com>
---
lib/librte_eal/freebsd/eal_thread.c | 19 +++++++++++++++----
lib/librte_eal/linux/eal_thread.c | 19 +++++++++++++++----
lib/librte_eal/windows/eal_thread.c | 19 +++++++++++++++----
3 files changed, 45 insertions(+), 12 deletions(-)
diff --git a/lib/librte_eal/freebsd/eal_thread.c b/lib/librte_eal/freebsd/eal_thread.c
index bbc3a8e98..17b8f3996 100644
--- a/lib/librte_eal/freebsd/eal_thread.c
+++ b/lib/librte_eal/freebsd/eal_thread.c
@@ -42,8 +42,12 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned worker_id)
if (lcore_config[worker_id].state != WAIT)
goto finish;
- lcore_config[worker_id].f = f;
lcore_config[worker_id].arg = arg;
+ /* Ensure that all the memory operations are completed
+ * before the worker thread starts running the function.
+ * Use worker thread function as the guard variable.
+ */
+ __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE);
/* send message */
n = 0;
@@ -100,6 +104,7 @@ eal_thread_loop(__rte_unused void *arg)
/* read on our pipe to get commands */
while (1) {
+ lcore_function_t *f;
void *fct_arg;
/* wait command */
@@ -119,12 +124,18 @@ eal_thread_loop(__rte_unused void *arg)
if (n < 0)
rte_panic("cannot write on configuration pipe\n");
- if (lcore_config[lcore_id].f == NULL)
- rte_panic("NULL function pointer\n");
+ /* Load 'f' with acquire order to ensure that
+ * the memory operations from the main thread
+ * are accessed only after update to 'f' is visible.
+ * Wait till the update to 'f' is visible to the worker.
+ */
+ while ((f = __atomic_load_n(&lcore_config[lcore_id].f,
+ __ATOMIC_ACQUIRE)) == NULL)
+ rte_pause();
/* call the function and store the return value */
fct_arg = lcore_config[lcore_id].arg;
- ret = lcore_config[lcore_id].f(fct_arg);
+ ret = f(fct_arg);
lcore_config[lcore_id].ret = ret;
lcore_config[lcore_id].f = NULL;
lcore_config[lcore_id].arg = NULL;
diff --git a/lib/librte_eal/linux/eal_thread.c b/lib/librte_eal/linux/eal_thread.c
index 8f3c0dafd..a0a009104 100644
--- a/lib/librte_eal/linux/eal_thread.c
+++ b/lib/librte_eal/linux/eal_thread.c
@@ -42,8 +42,12 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned int worker_id)
if (lcore_config[worker_id].state != WAIT)
goto finish;
- lcore_config[worker_id].f = f;
lcore_config[worker_id].arg = arg;
+ /* Ensure that all the memory operations are completed
+ * before the worker thread starts running the function.
+ * Use worker thread function as the guard variable.
+ */
+ __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE);
/* send message */
n = 0;
@@ -100,6 +104,7 @@ eal_thread_loop(__rte_unused void *arg)
/* read on our pipe to get commands */
while (1) {
+ lcore_function_t *f;
void *fct_arg;
/* wait command */
@@ -119,12 +124,18 @@ eal_thread_loop(__rte_unused void *arg)
if (n < 0)
rte_panic("cannot write on configuration pipe\n");
- if (lcore_config[lcore_id].f == NULL)
- rte_panic("NULL function pointer\n");
+ /* Load 'f' with acquire order to ensure that
+ * the memory operations from the main thread
+ * are accessed only after update to 'f' is visible.
+ * Wait till the update to 'f' is visible to the worker.
+ */
+ while ((f = __atomic_load_n(&lcore_config[lcore_id].f,
+ __ATOMIC_ACQUIRE)) == NULL)
+ rte_pause();
/* call the function and store the return value */
fct_arg = lcore_config[lcore_id].arg;
- ret = lcore_config[lcore_id].f(fct_arg);
+ ret = f(fct_arg);
lcore_config[lcore_id].ret = ret;
lcore_config[lcore_id].f = NULL;
lcore_config[lcore_id].arg = NULL;
diff --git a/lib/librte_eal/windows/eal_thread.c b/lib/librte_eal/windows/eal_thread.c
index b69672fe0..7a9277c51 100644
--- a/lib/librte_eal/windows/eal_thread.c
+++ b/lib/librte_eal/windows/eal_thread.c
@@ -32,8 +32,12 @@ rte_eal_remote_launch(lcore_function_t *f, void *arg, unsigned int worker_id)
if (lcore_config[worker_id].state != WAIT)
return -EBUSY;
- lcore_config[worker_id].f = f;
lcore_config[worker_id].arg = arg;
+ /* Ensure that all the memory operations are completed
+ * before the worker thread starts running the function.
+ * Use worker thread function as the guard variable.
+ */
+ __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE);
/* send message */
n = 0;
@@ -84,6 +88,7 @@ eal_thread_loop(void *arg __rte_unused)
/* read on our pipe to get commands */
while (1) {
+ lcore_function_t *f;
void *fct_arg;
/* wait command */
@@ -103,12 +108,18 @@ eal_thread_loop(void *arg __rte_unused)
if (n < 0)
rte_panic("cannot write on configuration pipe\n");
- if (lcore_config[lcore_id].f == NULL)
- rte_panic("NULL function pointer\n");
+ /* Load 'f' with acquire order to ensure that
+ * the memory operations from the main thread
+ * are accessed only after update to 'f' is visible.
+ * Wait till the update to 'f' is visible to the worker.
+ */
+ while ((f = __atomic_load_n(&lcore_config[lcore_id].f,
+ __ATOMIC_ACQUIRE)) == NULL)
+ rte_pause();
/* call the function and store the return value */
fct_arg = lcore_config[lcore_id].arg;
- ret = lcore_config[lcore_id].f(fct_arg);
+ ret = f(fct_arg);
lcore_config[lcore_id].ret = ret;
lcore_config[lcore_id].f = NULL;
lcore_config[lcore_id].arg = NULL;
--
2.17.1
next prev parent reply other threads:[~2021-02-24 21:20 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-24 21:20 [dpdk-dev] [RFC 0/5] Use correct memory ordering in eal functions Honnappa Nagarahalli
2021-02-24 21:20 ` [dpdk-dev] [RFC 1/5] eal: reset lcore function pointer and argument Honnappa Nagarahalli
2021-02-24 21:20 ` Honnappa Nagarahalli [this message]
2021-02-24 21:20 ` [dpdk-dev] [RFC 3/5] eal: lcore state FINISHED is not required Honnappa Nagarahalli
[not found] ` <AM5PR0802MB2465B62994239817E0AC46C59E9E9@AM5PR0802MB2465.eurprd08.prod.outlook.com>
2021-02-25 8:44 ` [dpdk-dev] 回复: " Feifei Wang
2021-02-25 23:33 ` [dpdk-dev] " Honnappa Nagarahalli
2021-02-26 8:26 ` Thomas Monjalon
2021-03-02 3:13 ` Honnappa Nagarahalli
2021-03-19 13:42 ` Ananyev, Konstantin
2021-03-30 2:54 ` Honnappa Nagarahalli
2021-03-01 5:55 ` [dpdk-dev] 回复: " Feifei Wang
2021-02-24 21:20 ` [dpdk-dev] [RFC 4/5] eal: ensure memory operations are visible to main Honnappa Nagarahalli
2021-02-24 21:20 ` [dpdk-dev] [RFC 5/5] test/ring: use relaxed barriers for ring stress test Honnappa Nagarahalli
2021-03-01 16:41 ` [dpdk-dev] [RFC 0/5] Use correct memory ordering in eal functions Stephen Hemminger
2021-03-02 16:06 ` Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 0/6] " Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 1/6] eal: reset lcore function pointer and argument Honnappa Nagarahalli
2021-09-10 7:49 ` Bruce Richardson
2021-09-10 8:12 ` David Marchand
2021-09-11 22:19 ` Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 2/6] eal: ensure memory operations are visible to worker Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 3/6] eal: lcore state FINISHED is not required Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 4/6] eal: update rte_eal_wait_lcore definition Honnappa Nagarahalli
2021-09-09 23:37 ` Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 5/6] eal: ensure memory operations are visible to main Honnappa Nagarahalli
2021-09-09 23:13 ` [dpdk-dev] [PATCH v2 6/6] test/ring: use relaxed barriers for ring stress test Honnappa Nagarahalli
2021-10-07 11:55 ` Ananyev, Konstantin
2021-10-07 23:40 ` Honnappa Nagarahalli
2021-10-25 4:52 ` [dpdk-dev] [PATCH v3 0/4] Use correct memory ordering in eal functions Honnappa Nagarahalli
2021-10-25 4:52 ` [dpdk-dev] [PATCH v3 1/4] eal: reset lcore function pointer and argument Honnappa Nagarahalli
2021-10-25 4:52 ` [dpdk-dev] [PATCH v3 2/4] eal: lcore state FINISHED is not required Honnappa Nagarahalli
2021-10-25 4:52 ` [dpdk-dev] [PATCH v3 3/4] eal: use correct memory ordering Honnappa Nagarahalli
2021-10-25 4:52 ` [dpdk-dev] [PATCH v3 4/4] test/ring: use relaxed barriers for ring stress test Honnappa Nagarahalli
2021-10-25 16:23 ` [dpdk-dev] [PATCH v3 0/4] Use correct memory ordering in eal functions David Marchand
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